RVuptakeLexiDiagnostic and Prognostic Value of the Stress Induced Right Ventricular Uptake on Lexiscan Stress MPI in Patients With Known or Suspected Coronary Artery Disease (CAD).

Phase 1: Retrospective data collection/analysis All Lexiscan and exercise MPI images on patients performed for clinical indications in calendar year 2010 who had subsequent coronary angiogram within 3 months after index MPI will be retrieved for review by two experts. We will identify different types of RV uptake and RV overload during stress as well as presence or absence of these changes on resting images. Analysis will include increased RV uptake, enlargement, hypertrophy, thinning of RV and flattening of the interventricular septum. Diagnostic performance (sensitivity, specificity and diagnostic accuracy) of the identified pathological RV phenotypes in identifying severe and extensive disease will be evaluated by comparison with contrary angiograms. Comparison of the set of parameters identifying pathological RV changes, identifying normal and abnormal values of these novel ancillary markers, as well as assessing their diagnostic accuracy in patients with suspected and known CAD during vasodilator stress versus exercise stress MPI will be done. Phase 2: Prospective data validation Patients referred for the Lexiscan stress MPI will be followed prospectively after obtaining an informed consent. All comers after June 1 2012 will be included. Prediction of coronary artery disease will be performed by applying the previously derived pathological RV criteria on the prospective stress MPIs. 2D-Echocardiogram will be performed for all the patients who do not have an Echocardiogram performed for clinical indication within 1 month of their index Lexiscan stress MPI. We will also include 100 patients referred for the exercise stress MPI who will serve as controls. All patients will be prospectively followed up for a total of 12 months for the following prognostic end points: Hard cardiac events (cardiac death or MI); Total (all-cause) mortality; Cardiovascular hospitalization rate. Cardiac death (CD) will be defined as death attributable to any cardiac cause (eg, lethal arrhythmia, myocardial infarction [MI], or pump failure) as confirmed by review of death certificate and medical records.